Encryptor is stateful. It's also reused when multiple runs of open entry stream is called. Need to change that. Need Pkware test.

src/SharpCompress/Common/Zip/PkwareTraditionalEncryptionData.cs

@@ -9,10 +9,11 @@ namespace SharpCompress.Common.Zip
     {
         private static readonly CRC32 crc32 = new CRC32();
         private readonly UInt32[] _Keys = {0x12345678, 0x23456789, 0x34567890};
+        private readonly string password;
 
         private PkwareTraditionalEncryptionData(string password)
         {
-            Initialize(password);
+            this.password = password;
         }
 
         private byte MagicByte
@@ -28,6 +29,7 @@ namespace SharpCompress.Common.Zip
                                                               byte[] encryptionHeader)
         {
             var encryptor = new PkwareTraditionalEncryptionData(password);
+            encryptor.InitializeKeys();
             byte[] plainTextHeader = encryptor.Decrypt(encryptionHeader, encryptionHeader.Length);
             if (plainTextHeader[11] != (byte)((header.Crc >> 24) & 0xff))
             {
@@ -84,7 +86,7 @@ namespace SharpCompress.Common.Zip
             return cipherText;
         }
 
-        private void Initialize(string password)
+        internal void InitializeKeys()
         {
             byte[] p = StringToByteArray(password);
             for (int i = 0; i < password.Length; i++)

src/SharpCompress/Common/Zip/ZipFilePart.cs

@@ -147,6 +147,7 @@ namespace SharpCompress.Common.Zip
             }
             if (Header.PkwareTraditionalEncryptionData != null)
             {
+                Header.PkwareTraditionalEncryptionData.InitializeKeys();
                 return new PkwareTraditionalCryptoStream(plainStream, Header.PkwareTraditionalEncryptionData,
                                                          CryptoMode.Decrypt);
             }

test/SharpCompress.Test/Zip/ZipArchiveTests.cs

@@ -183,6 +183,32 @@ namespace SharpCompress.Test
             Assert.Equal(new FileInfo(scratchPath1).Length, new FileInfo(scratchPath2).Length);
         }
 
+        [Fact]
+        public void Zip_Read_Entry_Twice()
+        {
+            string scratchPath = "C:\\Users\\adam\\Downloads\\Archive1.zip";
+
+            using (var archive = ArchiveFactory.Open(scratchPath, new ReaderOptions()
+                                                                  {
+                                                                      Password = "12345678"
+            }))
+            {
+                var entries = archive.Entries.Where(entry => !entry.IsDirectory);
+
+                foreach (var entry in entries)
+                {
+                    for (int i = 0; i < 2; i++)
+                    {
+                        using (var memoryStream = new MemoryStream())
+                        using (var entryStream = entry.OpenEntryStream())
+                        {
+                            entryStream.CopyTo(memoryStream);
+                        }
+                    }
+                }
+            }
+        }
+
         [Fact]
         public void Zip_Removal_Poly()
         {